The present invention relates to video signal processing in which commercials are selectively inserted into video signal material, and more particularly relates to methods and apparatuses for processing a video (or audio) signal so as to reduce or remove the effectiveness or effects of commercial skip systems such as those presently found in video recorders.
Other methods and apparatuses of the invention relate to at least partially restoring the effectiveness of a commercial skip system which has been reduced or defeated, for example, by the above-mentioned methods and apparatuses.
Currently there are personal video recorders (PVRs) and video cassette recorders (VCRs) which have been modified to include commercial skip circuits which detect the presence of commercials in a recorded video program, and then mark the locations of the commercial for subsequent deletions. To this end, in one version of a commercial skip system, when the recorders are used to record a program, the entire program including the commercials are recorded. If the skip system in the recorder is activated, the recording is shuttled to allow the skip system to detect and then mark the beginning of the commercials in the program. In this embodiment of a commercial skip system, as the marked recording is subsequently played back, the marks indicating a commercial are detected and the recording is for example fast forwarded past the commercial to the point where the program is resumed. Thus, the commercials are, in effect, skipped.
Such a commercial skip system is described for example in U.S. Pat. Nos. 5,333,091 ('091), 5,692,093 ('093) and 5,696,866 ('866) all by Iggulden et al. This system, called “Commercial Advance” system, which has been implemented in some VCRs sold in the US market, employs two basic steps for providing commercial detection and deletion (that is, skipping). In the first step, the Commercial Advance system uses a video event detector, and also may include an audio event detector to detect relevant video events and audio events. The video event detector is mainly based on the detection of black or dark video frames that are frequently observed between commercials. The audio event detector detects generally low audio signals between commercials. By detecting dark video frames (and also “silent scene,” low audio signals), Commercial Advance method marks the events and stores them into an event list that can be analyzed later by its commercial detection method in the second step. The commercial detection method detects multiple groups of commercials based on the event list and a set of rules such as the typical commercial length (e.g., 30 seconds) and minimum number of commercials within each group of commercials.
It is readily apparent that a commercial skip system such as those disclosed in the patents ('091), ('093) and ('866) of previous mention rely on analyzing a video data stream for specific timing of detectable events such as blank or black video frames indicative of essentially two portions of the video data stream; commercials and non-commercials. The system stores the timing of the detectable events and then generates a classification signal based on the storage of the detectable events, to thereby cause the skipping of commercials during the subsequent (at least second) playback of the analyzed data stream. It follows that the Commercial Advance system of patents ('091), ('093) and ('866) does not skip commercials in real time or near real time.
In prior art of interest relative to the present invention, U.S. patent application Publications 2003/0001977 A1 ('1977) and 2002/0191950 A1 ('1950) both to X. Wang, disclose apparatus and method for preventing automated commercial detection and is comprised of a commercial transition localization device, a circuit for generating a classification signal and a subsequently applied commercial transition modification device. The commercial transition localization device localizes all commercial transitions within a given video signal after a first examination of the video program and supplies the information to the commercial transition modification device in a later playback process. In a subsequent replay of the video signal, the commercial transition modification device generates a new transition for each found original commercial transition, and replaces the original transitions with the new transitions. The new generated commercial transitions are designed in such a way that they are in general not detectable by automated commercial detection methods used by common commercial detection and elimination systems such as the Commercial Advance system of previous mention. Thus it may be seen that the system disclosed in the patent application publications to Wang is based upon and relies on the two step, non real time technique disclosed in the U.S. Pat. Nos. ('091), ('093) and ('866) discussed previously.
In a version of the system disclosed in publications ('1977) and ('1950) wherein the classification signal is derived automatically, during recording of the video program the derived classification signal requires a memory (RAM) along with a microprocessor and another memory (ROM) for providing analysis. The classification information is stored in the RAM in association with the video signal's time code or time identification to provide the means for controlling the precise timing when subsequently playing back the video program. To provide a workable system it is readily apparent that the video signal, i.e., program, must be played twice. That is, the video program is played a first time to allow for generation of the classification signal, which has a specific timing with respect of the time code of the video program. Subsequently, the video program must be played a second time to synchronize it with the previously stored classification signal, whereupon the normal commercial transitions are replaced with the modified transitions as shown for example in FIGS. 1-3 of the Publication ('1977). Notice that the video signal is not modified outside of the commercial transitions.
In a second version of the system disclosed in Publications ('1977) and ('1950), the classification signal, which identifies the commercial and non-commercial portions of the whole video program, is derived manually. In this version, the video program is played and rewound multiple times to retrieve the exact time locations of each of the many groups of commercials and corresponding commercial transitions. Then after the entire video program is analyzed manually, the manually compiled classification signal is timed with the video program's time code to allow the commercials to be detected and played upon the second playback of the video program, thereby defeating the commercial skip system. As is readily apparent, the system of Publications ('1977) and ('1950) provides for the defeat of a commercial skip system, such as Commercial Advance, in non real time.
It follows that the system of the Publications ('1977) and/or ('1950) does not provide a commercial skip defeat process which operates in real time, nor does it modify the video signal outside of the commercial transitions. That is, the system requires the use of a classification signal, the use of timecode marking on the recorded video program, and the playback of the recorded video program a second time in non real time. The latter drawback produces an unacceptable delay in broadcasting the video program due to the fact that the material must be played back at least a second time. The delay is at least the duration of the video program. For example, a 30 minute program with commercials will produce at least a 30 minute delay before being played back.
Further, the system of the Publications ('1977) and ('1950) relies on a commercial transition modification device which generates a new modified commercial transition for each original commercial transition detected, and replaces the original transitions with the new modified transitions. It follows then that each original commercial transition first must be detected before it can be replaced upon a second playback of the video signal.
However, it is appreciated that production and/or broadcast companies, which depend on income from the presentation of commercials in their programs material, prefer that the effects of commercial skip systems such as Commercial Advance installed in VCRs, PVRs and other recorders, be nullified or otherwise overcome.